1. Field of the Invention.
The field of the invention relates to an innerspring construction including strings of pocketed coil springs interconnected by a hot melt adhesive or the like along the tangential lines of intersection of the adjacent strings. A method for manufacturing such a construction is also provided.
2. Brief Description of the Prior Art.
Innerspring constructions including pocketed coil springs have been manufactured for many years and offer certain advantages over competitive assemblies. Various means have been used to connect adjacent rows or strings of pocketed springs.
U.S. Pat. No. 698,529 to Marshall discloses strings of coils connected by links to form a square arrangement. A different arrangement including hog rings is provided in U.S. Pat. No. 2,320,153. Utilization of such rings is slow and expensive as the operator not only has to position the coils, but has to apply a hog ring by piercing the pocket wrap material and catching the wire defining the top convolution of the coil.
U.S. Pat. No. 2,862,214 concerns a cushion including a string of pocketed coils which is folded back and forth within a cavity formed by side wall pads. The springs are held in position by mutual engagement as well as by the surrounding side wall pads. The interior surfaces of the cover and bottom pads are coated with an adhesive. The fabric strip which defines the spring compartments may be coated with an adhesive either in its entirety or at the ends of the compartments. Such procedures yieldably maintain the springs in their individual positions.
U.S. Pat. No. 4,393,792 discloses an apparatus for assembling innerspring constructions by pulling lengths of twine therethrough with needles. This produces a nested array of pocketed coil springs. The assembly process is labor and material intensive. The operator positions coils on the rack and forces them to a nesting pattern. Needles are actuated which pierce the racked construction. Assembly strings are applied and tied off with the tightness of the assembly being dependent on operator skill.
A square array of pocketed springs is disclosed in U.S. Pat. No. 4,234,984. Adjacent strings of coils are secured to each other along the fabric connecting alternating coil springs. A structure having a clover leaf pattern is accordingly obtained.